Source : Webster's Revised Unabridged Dictionary (1913)

Bass \Bass\, n. [A corruption of bast.]
   1. (Bot.) The linden or lime tree, sometimes wrongly called
      {whitewood}; also, its bark, which is used for making
      mats. See {Bast}.

   2. (Pron. ?) A hassock or thick mat.

Bass \Bass\, n. [F. basse, fr. bas low. See {Base}, a.]
   1. A bass, or deep, sound or tone.

   2. (Mus.)
      (a) The lowest part in a musical composition.
      (b) One who sings, or the instrument which plays, bass.
          [Written also {base}.]

   {Thorough bass}. See {Thorough bass}.

Bass \Bass\, a.
   Deep or grave in tone.

   {Bass clef} (Mus.), the character placed at the beginning of
      the staff containing the bass part of a musical
      composition. [See Illust. under {Clef}.]

   {Bass voice}, a deep-sounding voice; a voice fitted for
      singing bass.

Bass \Bass\, n.; pl. {Bass}, and sometimes {Basses}. [A
   corruption of barse.] (Zo["o]l.)
   1. An edible, spiny-finned fish, esp. of the genera {Roccus},
      {Labrax}, and related genera. There are many species.

   Note: The common European bass is {Labrax lupus}. American
         species are: the striped bass ({Roccus lineatus});
         white or silver bass of the lakes. ({R. chrysops});
         brass or yellow bass ({R. interruptus}).

   2. The two American fresh-water species of black bass (genus
      {Micropterus}). See {Black bass}.

   3. Species of {Serranus}, the sea bass and rock bass. See
      {Sea bass}.

   4. The southern, red, or channel bass ({Sci[ae]na ocellata}).
      See {Redfish}.

   Note: The name is also applied to many other fishes. See
         {Calico bass}, under {Calico}.

Bass \Bass\, n.; pl. {Bass}, and sometimes {Basses}. [A
   corruption of barse.] (Zo["o]l.)
   1. An edible, spiny-finned fish, esp. of the genera {Roccus},
      {Labrax}, and related genera. There are many species.

   Note: The common European bass is {Labrax lupus}. American
         species are: the striped bass ({Roccus lineatus});
         white or silver bass of the lakes. ({R. chrysops});
         brass or yellow bass ({R. interruptus}).

   2. The two American fresh-water species of black bass (genus
      {Micropterus}). See {Black bass}.

   3. Species of {Serranus}, the sea bass and rock bass. See
      {Sea bass}.

   4. The southern, red, or channel bass ({Sci[ae]na ocellata}).
      See {Redfish}.

   Note: The name is also applied to many other fishes. See
         {Calico bass}, under {Calico}.

Bass \Bass\, v. t.
   To sound in a deep tone. [R.] --Shak.

Source : WordNet®

bass
     adj : having or denoting a low vocal or instrumental range; "a
           deep voice"; "a bass voice is lower than a baritone
           voice"; "a bass clarinet" [syn: {deep}]

bass
     n 1: the lowest part of the musical range
     2: the lowest part in polyphonic music [syn: {bass part}]
     3: an adult male singer with the lowest voice [syn: {basso}]
     4: the lean flesh of a saltwater fish of the family Serranidae
        [syn: {sea bass}]
     5: any of various North American freshwater fish with lean
        flesh (especially of the genus Micropterus) [syn: {freshwater
        bass}]
     6: the lowest adult male singing voice [syn: {bass voice}, {basso}]
     7: the member with the lowest range of a family of musical
        instruments
     8: nontechnical name for any of numerous edible marine and
        freshwater spiny-finned fishes